The present invention relates to a device for deshirring, smoothing and braking a shirred tubular casing into which a fluid mass, such as a sausage mixture, flows under pressure from the stuffing horn of a stuffing machine. The invention also relates to an apparatus comprising such a device.
It is known to use shirred, tubular casings of synthetic, semi-synthetic or natural materials for packing fluid foodstuffs, such as meat products in the form of sausages. These casings, which are known in the trade as "sticks" or "hollow rod" are produced by gathering and longitudinally compressing long casings, whereby the length of the shirred casing is usually reduced to only one to three percent of the original length. In general, a shirred tubular casing which has been closed at one end is initially placed on the stuffing horn of a sausage stuffing machine in order to be filled with the sausage mixture. The sausage mixture is then forced under pressure through the stuffing horn into the casing, which is thereby continuously deshirred. After a predetermined length has been reached, cylindrical sausages are closed and tied off.
For various reasons, the diameter of the sausages which are produced should remain constant over their entire length. Only a uniform diameter, the size of which depends on the casing material, for example, assures that the stuffing operation will proceed in an optimum manner. Also, if the sausage casing is overfilled, there is a danger it may burst, while if the sausage casing is underfilled, it will have a wrinkled surface.
Various devices have heretofore been proposed for stuffing a sausage mixture into a shirred tubular casing in which special arrangements for deshirring, smoothing and braking are provided to achieve the most uniform diameter possible for the stuffed casing.
Thus, U.S. Pat. No. 4,202,075 describes a device for deshirring, smoothing and braking a shirred tubular casing which comprises an annular body of flexible material which spreads or stretches the tubular casing. On the outer surface of the annular body there are raised portions or recesses which can be extended by means of a second calibrating piece located in the interior of the annular body so that the circumference of the annular body is then enlarged. During the stuffing operation, the inner surface of the tubular casing slides over the outer surface of the annular body and is spread and expanded until it is deshirred and smoothed. The friction between the outer surface of the annular body and the inner surface of the tubular casing increases as the circumference of the annular body expands. By means of this friction, the withdrawal of the tubular casing during the stuffing operation is braked. However, the braking effect of the annular body generally remains small because of the limited expansibility of the annular body. Therefore, an additional braking element is required adjacent the stuffing horn outlet which presses the tubular casing which has been deshirred and smoothed by the annular body against the outer surface of the stuffing horn.